<?php // $Id: loginas.php,v 1.47.2.2 2008/01/10 15:09:10 skodak Exp $
	  // Allows a teacher/admin to login as another user (in stealth mode)

	require_once('../config.php');
	require_once('lib.php');

/// Reset user back to their real self if needed
	$return = optional_param('return', 0, PARAM_BOOL);   // return to the page we came from

	if (!empty($USER->realuser)) {
		if (!confirm_sesskey()) {
			print_error('confirmsesskeybad');
		}

		$USER = get_complete_user_data('id', $USER->realuser);
		load_all_capabilities();   // load all this user's normal capabilities

		if (isset($SESSION->oldcurrentgroup)) {	  // Restore previous "current group" cache.
			$SESSION->currentgroup = $SESSION->oldcurrentgroup;
			unset($SESSION->oldcurrentgroup);
		}
		if (isset($SESSION->oldtimeaccess)) {		// Restore previous timeaccess settings
			$USER->timeaccess = $SESSION->oldtimeaccess;
			unset($SESSION->oldtimeaccess);
		}
		if (isset($SESSION->grade_last_report)) {	// Restore grade defaults if any
			$USER->grade_last_report = $SESSION->grade_last_report;
			unset($SESSION->grade_last_report);
		}

		if ($return and isset($_SERVER["HTTP_REFERER"])) { // That's all we wanted to do, so let's go back
			redirect($_SERVER["HTTP_REFERER"]);
		} else {
			redirect($CFG->wwwroot);
		}
	}

///-------------------------------------
/// We are trying to log in as this user in the first place

	$id	 = optional_param('id', SITEID, PARAM_INT);   // course id
	$userid = required_param('user', PARAM_INT);		 // login as this user

	if (!confirm_sesskey()) {
		print_error('confirmsesskeybad');
	}

	if (! $course = get_record('course', 'id', $id)) {
		error("Course ID was incorrect");
	}

/// User must be logged in

	$systemcontext = get_context_instance(CONTEXT_SYSTEM);
	$coursecontext = get_context_instance(CONTEXT_COURSE, $course->id);

	require_login();

	if (has_capability('moodle/user:loginas', $systemcontext)) {
		if (has_capability('moodle/site:doanything', $systemcontext, $userid, false)) {
			print_error('nologinas');
		}
		$context = $systemcontext;
	} else {
		require_login($course);
		require_capability('moodle/user:loginas', $coursecontext);
		if (!has_capability('moodle/course:view', $coursecontext, $userid, false)) {
			error('This user is not in this course!');
		}
		if (has_capability('moodle/site:doanything', $coursecontext, $userid, false)) {
			print_error('nologinas');
		}
		$context = $coursecontext;
	}

/// Remember current timeaccess settings for later

	if (isset($USER->timeaccess)) {
		$SESSION->oldtimeaccess = $USER->timeaccess;
	}
	if (isset($USER->grade_last_report)) {
		$SESSION->grade_last_report = $USER->grade_last_report;
	}

/// Login as this user and return to course home page.

	$oldfullname = fullname($USER, true);
	$olduserid   = $USER->id;

/// Create the new USER object with all details and reload needed capabilitites
	$USER = get_complete_user_data('id', $userid);
	$USER->realuser = $olduserid;
	$USER->loginascontext = $context;
	check_enrolment_plugins($USER);
	load_all_capabilities();   // reload capabilities

	if (isset($SESSION->currentgroup)) {	// Remember current cache setting for later
		$SESSION->oldcurrentgroup = $SESSION->currentgroup;
		unset($SESSION->currentgroup);
	}

	$newfullname = fullname($USER, true);

	add_to_log($course->id, "course", "loginas", "../user/view.php?id=$course->id&amp;user=$userid", "$oldfullname -> $newfullname");

	$strloginas	= get_string('loginas');
	$strloggedinas = get_string('loggedinas', '', $newfullname);

	print_header_simple($strloggedinas, '', build_navigation(array(array('name'=>$strloggedinas, 'link'=>'','type'=>'misc'))),
			'', '', true, '&nbsp;', navmenu($course));
	notice($strloggedinas, "$CFG->wwwroot/course/view.php?id=$course->id");


?>
